Process for treating synthetic textiles



stances with which the Patented Sept. 14, 1954 tans PROCESS FOR TREATINGSYNTHETIC TEXTILES John Donald Martone, Wilmington, Del., assignor to E.I. du Pont Wilmington, DeL,

de Nemours and Company, a corporation of Delaware No Drawing.Application January 31, 1952, Serial No. 269,343

Claims.

This invention relates to a method for treating textiles composed ofpolymers and copolymers of acrylonitrile. More particularly, it relatesto a process for treating textiles such as the filaments, fibers, yarns,staple, fabrics, and the like, of polymers and copolymers ofacrylonitrile to permit uniform darkening when they are exposed to anelevated temperature.

It is a matter of common knowledge that textiles, such as the filaments,fibers, yarns, staple, fabrics, and the like, produced from polymers andcopolymers of acrylonitrile darken when they are exposed to an elevatedtemperature. Fur thermore, it has been observed that this darkening isnot uniform. In the case of fabrics, warp streaks, filling barre, andthe like result, which in many instances destroy the commercial value ofthe material. The temperatures experienced upon exposure to the weather,as for instance upon awnings, auto tops, and the like, as well as thosedue to frictional sources, as upon machinery drive belts, and the like,have been found to produce the unsightly effect.

It is an object of this invention to provide a process for the treatmentof textiles such as filaments, fibers, yarns, staple, fabrics, and thelike, of polymers and copolymers of acrylonitrile which will eliminatethe variable darkening tendency on exposure to an elevated temperature.

A further object is to produce a textile such as a filament, fiber,yarn, staple, fabric, or the like, of polymers and copolymers ofacrylonitrile which darkens uniformly on exposure to an elevatedtemperature. 7

These and other objects will become apparent in the course of thefollowing specification and claims.

The objects of the present invention are accomplished by subjecting thetextile such as the filament, fiber, yarn, staple, fabric, or the like,to a treatment comprising the following steps:

1. scouring, with or without a suitable detergent, to remove size,finish material or other subtextile has been coated.

2. Boiling-off in an aqueous solution of a low molecular weightaliphatic carboxylic acid containing minor amounts of a sulfate of along chain aliphatic alcohol.

3. Rinsing with soft water to remove traces of acid.

After such treatment, the textile of polymers or copolymers ofacrylonitrile may be subjected to an elevated temperature withoutstreaking due to non-uniform darkening.

The following example is cited by way of illustration and not by way oflimitation.

Example A swatch 12" x 12', woven in a x 82 construction, taffetapattern from denier continuous filament polyacrylonitrile yarn whichcontains a coating of gelatin as a size, is secured in a bath containing0.2% of the sodium sulfate of commercial lauryl alcohol as a detergent.At the end of 30 minutes, the swatch is boiled-off (212 F.) for twohours in an aqueous solution containing 2% oxalic acid and 0.2% of acommercial mixture of a sodium sulfate oi commercial lauryl alcohol. Theswatch is then rinsed with soft water until free of residual acid.Thereafter, the fabric is air dried at a temperature of approximately180 F.

Upon subjecting the swatch to a temperature of 350 F. for 3 minutes, thematerial darkened appreciably. However, this darkening is uniform, freefrom filling barre, warp streaks, and the like.

When a swatch of the same material is subjected to heat in accordancewith the conditions of the procedure outlined above, without thepretreatment described, a non-uniform darkening is observed showingpronounced short length variations, warp streaks and filling barre.

By a textile of polymer of acrylonitrile is meant the filament, fiber,yarn, staple, fabric, and the like, produced by extrusion of polymerizedacrylonitrile, such as is illustrated in United States Patent No.2,404,714 to Latham dated July 23, 1946. Furthermore, copolymers ofacrylonitrile, wherein the acrylonitrile comprises about 35% or more arelikewise suitable. Among the copolymerizable compounds which may bemertioned as being suitable are methyl methacrylate, vinyl acetate,methyl vinyl ketone, vinyl pyridine, etc. Such copolymeric materials andothers are shown in United States Patents Nos. 2,436,926 to Jacobson,dated March 2, 1948, and 2,49lfl7i to Arnold, dated December 20, 1949.

While the example cited above illustrates the use of oxalic acid as thelow molecular weight aliphatic carboxylic acid, other such water-solubleorganic acids may be used as well. Among these may be mentioned formic,propionic and acetic. Oxalic acid is preferred since it appears to giveoptimum results under the conditions outlined. Acid concentrations willvary somewhat, depending on the acid. A 1% to 2% solution has been foundeifective for oxalic acid.

filament yarn or from spun yarn of staple or from mixtures of theseyarns. While the invention is primarily concerned with fabrics ofpolymers or copolymers of acrylonitrile, it is also useful and period ofscouring will b governed by the type of finish and the effectiveness ofthe detergent used.

The boiling-off step in the acid and aliphatic alcohol sulfate isusually acaqueous solution. he lower concenable. No deleterious effectsresult from extended periods of contact.

The rinsing step can be accomplished by any conventional method, such asimmersion, spraying, or the like. The wash water may be reis not inexcess of 300 F.

While the specific example has been drawn to the pretreatment of afabric prior to exposure What is claimed is: 1. A process for thetreatment of a textile comrinsing with water.

2. The process of claim 1 wherein the low molecular weight aliphaticcarboxylic acid is oxalic acid.

4. The process of claim 3 wherein the sulfate of the long chainaliphatic alcohol is the sulfate of a mixture prepared by the hydrationof alkenes formed in the cracking of petroleum.

5. The process of claim 3 wherein the sulfate of the long chainaliphatic alcohol is the sulfate of lauryl alcohol.

6. A process for the treatment of a textile comprising a member of thegroup consisting of 7. The process of claim 6 wherein the textile is afabric.

8. The process of claim 7 wherein the acid is oxalic and the alcohol islauryl alcohol.

9. A process for the treatment of a nitrile textile which comprises thesteps of scouris thereafter uniformly darkened by subjecting it C. forabout 3 References Cited in the file of this patent UNITED STATESPATENTS Number Name Date 2,404,357 Bechtold July 23, 1946 2,431,956Moody Dec. 2, 1947 FOREIGN PATENTS Number Country Date 905,038 FranceNov. 22, 1945

1. A PROCESS FOR THE TREATMENT OF A TEXTILE COMPRISING A MEMBER OF THEGROUP CONSISTING OF POLYMERS AND COPOLYMERS OF ACRYLONITRILE PRIOR TOEXPOSURE TO ELEVATED TEMPERATURES WHICH COMPRISES THE STEPS OF SCOURINGTHE TEXTILE, CONTACTING IT FOR A PERIOD OF ABOUT ONE HOUR WITH A BOILINGAQUEOUS SOLUTION OF A LOW MOLECULAR WEIGHT ALIPAHATIC CARBOXYLIC ACIDCONTAINING A MINOR AMOUNT OF A SULFATE OF A LONG CHAIN ALIPHATIC ALCOHOLAND RINSING WITH WATER.